The most important lesson
by fire-forged
Summary: Snape is put in charge of training Harry for his duel with Voldemort. But the lesson that Harry most needs to learn may be the most difficult one to teach. Complete! R&R please!
1. A favour

Disclaimer: This story was written purely for fun. I do not own any of the characters or make any money out of this.

A/N: This story is set at the beginning of Harry's sixth year, and is quite AU. It disregards HPB completely. I tried to keep Snape as much in character as I could. This chapter is quite short, I intend it only as an introduction to what is to come. The next chapter should be up tomorrow. I hope you enjoy!

Warning: contains Snape torture.

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Chapter 1: A favour

There was a knock on the office door and Dumbledore looked up.

"Come in!"

The door opened to admit a familiar figure, dressed in black robes, with a black cloak that billowed behind him as he walked. Nodding to Dumbledore in greeting, he moved to stand in front of him, silently waiting for him to start speaking.

"Ah! Severus, I was waiting for you. Please have a seat."

Snape complied, and waited with a scowl on his face as Dumbledore moved to the window, staring outside and humming the tune to some children's song softly under his breath. It would do no good to rush him. Dumbledore would only talk when he was ready, probably after a lot of pointless chitchat.

"It's a beautiful day today, isn't it Severus?" Dumbledore questioned from his place at the window.

Snape only rolled his eyes in reply. He couldn't stand such inane talk. Yes, it was a bright sunny day, the flowers were blooming, the birds were chirping and all that, but what did that have to do with the reason he was here?

As if sensing the other's impatience, Dumbledore turned away from the window and moved to sit at his desk, elbows on the table, chin resting on his steepled fingers. He paused, considering carefully what he was about to say, then began, "Severus, I have called you here to ask a favour of you. I know you are not going to like it, but regrettably it has to be done."

Eying Dumbledore suspiciously, Snape gestured for him to go on.

"Voldemort is gaining power and followers day by day, and as you yourself have told me he is likely to be planning to again attack Harry whom he still, perhaps truly, believes to be his greatest obstacle. The prophecy too speaks of a final battle between Harry and Voldemort, and much as I would like to protect him from this, I believe it prudent to at least prepare him for an eventuality that we may not be able to prevent. It would be a great tragedy if Harry had to face Voldemort again as unprepared as he was last time. I trust you agree with me till this point?"

Snape nodded uncertainly, not sure where this was heading. "No doubt Potter needs to be trained, Dumbledore. In his current state the Dark Lord will hardly have to bat an eyelid to kill him. But I fail to see where I come in all of this…"

Snape faltered a bit as he saw the look in Dumbledore's eyes. He could see the answer there, before he had even asked the question. Comprehension dawned upon him, and he suddenly stood up, moving quickly backwards to the door.  
"No, Dumbledore. Do not even think it. I will not be the one training that insufferable boy. I will _not_ do it."

"Severus," Dumbledore said, fixing him with a steady gaze that stopped him in his tracks. "I need you to do this. I am sorry. I am aware of the …let's say… less than pleasant feelings you have for each other, but this is too important to let that stop us."

"Why me?" Snape protested. "You are a better duellist than me, why can't you teach him how to fight?"

"Because no one knows the dark lord as good as you do. No one understands his fighting style as well as you. And do not try to be modest, my boy, you would not have survived so long were not your duelling skills at least on par with mine." Dumbledore replied, a twinkle in his eyes.

"But…"

Dumbledore put up a hand to forestall any further arguments. "Enough," he said in a slightly harder tone. "I will instruct Potter to meet you in your office at 8 on Monday evening. The exact contents of your lessons I will leave up to you and your judgment on what you think will help Harry the most against Voldemort. Good night Severus and thank you."

Scowling at Dumbledore but knowing there was no way to change his mind about this, Snape only nodded curtly and left the room, slamming the door behind him a little harder than necessary.

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A/N: Review please! 


	2. An unusual lesson

Disclaimer: See first chapter

A/N: Here's the second chapter of the story. Thank you to all who have shown interest in this so far, and hope you enjoy this as well!

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Chapter 2: An unusual lesson

Monday evening came faster than Snape would have liked. He had given much thought to what he would need to teach and had reached an unpleasant but necessary decision. He was quite sure that what he had planned was very different from what Dumbledore and the boy himself had expected but it was perhaps the most important thing Potter would have to learn. He absolutely loathed having to do this, but there was simply no other way around it and Dumbledore was right, this task was too important to let his feelings get in the way. Knowing all this however, did not help to make it any less distasteful.

Glaring at the apprehensive boy standing in front of him now, as if he was the one to blame for all this (which, as far as Snape was concerned he was), he began, "Potter, you no doubt remember the prophecy the headmaster told you about, and if you have managed to retain any information in that head of yours you will know that you must face the Dark Lord in battle, ultimately to kill him or be killed, though I am not quite sure which outcome I am hoping for."

Smirking at the familiar signs of the rising anger in the boy standing in front of him – the clenched fist, the determined glare-Snape continued.

"Now I will assume that even an imbecile like you can see the need for you, given the situation, to learn how to defend yourself. But more importantly, you must remember that your objective is to kill him, not just disarm him or stun him like you have done to his death eaters before, but kill him. Which means you have to learn to _kill_."

Snape paused slightly to let that sink in. He could see that the full realisation of it was only hitting Potter now. What did the boy think? He was just going to arrive in front of the Dark Lord in a blaze of glory, in golden armour, and by the might of his righteousness and nobleness smote the evil villain to the ground? Hadn't he actually considered that he would have to learn to _kill_, to commit the act of murder? Killing was never as easy as the innocent believed. He knew what it felt like.

"Avada Kedavra…" Harry whispered, bringing Snape out of his thoughts.

Snape nodded. "Yes Potter, the Avada Kedavra.. The ultimate unblockable killing curse. The unforgivable. That it what you must learn to cast if you are to have any hope of victory, and that it is what I am going to teach you. It is not something that you will be able to cast effectively on the spur of the moment, without having practiced for it before."

Harry's head jerked up in surprise. He absorbed this information then questioned, "How are we going to practise that, sir?"

Snape set his jaw as he launched into the next part of his explanation. He had a feeling Potter would not like it very much, though he didn't really see why he had any right to complain.

"Well obviously we will be unable to find any willing volunteers for you to practice the killing curse on. The next best solution then is to practice another Unforgivable instead. The three Unforgivable spells, Potter, require similar skills, only different amounts of power. By practicing another one, we can hope that when the time comes you will be able to perform Avada Kedavra as well. For now, Potter, you will perform the Cruciatus curse on me."

Ignoring the way Potter's jaw dropped, Snape went on boldly before there could be any protests.

"You will cast the Cruciatus curse. You will try to hold it on me for as long as you possibly can. You probably won't be able to hold it for very long right now, but with practice I will ensure that you are able to cast much more powerful ones."

"Sir…"

Ignoring him once again, Snape continued, "For now, I will not attempt to resist or fight back your curse in any way, I will stand in front of you wandless. However, as you get better, we will attempt to use it in a duel situation, where you will not be given time to focus your concentration before using it, and will be expected to cast it on the spot, again and again until one finally hits.

"Sir!"

"What is it, Potter!" Snape finally snapped, thoroughly annoyed at him. It was not as if he was enjoying this any more than the boy – he had much better things to do with his Monday evenings than be tortured at the hands of an insolent brat, that brat being Harry Potter making it even worse - but there was no other way for Harry to practice the Unforgivables, and he had to be able to cast them or else they might as well hand Voldemort the victory now. Why couldn't the boy just get it done and over with rather than bothering him with pointless interruptions?

"Sir, couldn't we…couldn't I practice on spiders or something. I mean, how can I cast it on you?"

Snape sighed inwardly. He had known that Potter's Gryffindor nobility would get in the way. "Do I detect a hint of sympathy for me, Potter?" He said, in a sneering tone. "Strange, I was under the impression that you wanted nothing more than to hex me into oblivion the first chance you got."

Harry's eyes blazed with anger, and Snape smirked faintly.

"As for your question, Potter, no we could not use spiders because, as I am sure someone with a little more brains than you possess would be able to tell you, it takes much more power to cast an Unforgivable on a human being as compared to an insect. It will certainly not help our cause if you were to kill the flies around the Dark Lord, now would it?"

Harry seemed about to protest again, but one look from Snape and he reluctantly clamped his mouth shut.

"Now if there are no more pointless arguments, I have to tell you one last thing. You are not to mention what is going on here to anyone, not to your band of rag-tags, not to any of your fan club, not even to Dumbledore."

Seeing the shocked look on Harry's face, Snape elaborated, " No Harry, Dumbledore does not know what we are doing. He knows only that I am training you, building up your duelling skills, but he does not know what form this training is taking, or no doubt he would not allow it. I am afraid he does not see eye-to-eye with me on my teaching methods, but since he left it to my judgment, I will continue with it. He will not hear about this. Do you understand?"

Although clearly uneasy about this 'lesson', Harry had no choice but to nod in agreement.

"Then, if you please, wand on the ready"

Snape moved some distance away before turning around to face Harry, a strange glitter in his eyes, his face a blank mask. Nodding curtly to him, he placed his wand between his teeth, and clenched down hard on it.

Harry was confused at first at this unexpected gesture, then understanding dawned on him. Snape was quite serious when he said no one would 'hear' of this, he was going to make sure there were no sounds, no screams to leak out of the door. Harry closed his eyes briefly, his heart beating in anguish for what he was about to do. There was no love lost between the two of them, that was for sure, but even then Harry could not bring himself to so coldly and casually cause unendurable pain to a defenceless person, even a person like Snape. Harry had never considered until this moment how hard it actually was to cast that kind of a spell. However, he had to learn. And with that thought in his mind, Harry opened his eyes, took a deep breath, and focused on one of the hardest spells he had ever learned. Pointing his wand directly at Snape, Harry tried to summon up all his hatred for the teacher but it was hard to hate someone when they were willingly waiting to be tortured at your hands. Trying to see past the Snape standing in front of him now, Harry instead imagined the sneering, smirking Snape that he knew so well, and putting as much power behind the spell as he could, yelled, "_Crucio!"_

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A/N: Review, please!


	3. Chapter 3

A/N: Thanks for all your reviews! I have replied to everyone who logged in. I hope this next chapter came soon enough, and hopefully you enjoy it. It continues three weeks after the last chapter. I know it looks continuous at the beginning, but it's not. It'll be explained further in the story.

Warning: Oh yes, Snape torture. It's not too bad though; at least I don't think so…

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Chapter 3

The spell hit him squarely in the chest, the vicious pain immediately overriding all his other senses, until all he was aware of was the agony that rode through every vein in his body. It felt like thousands of invisible knives were being pushed into every square inch of his body, and then being twisted, slowly, their red hot blades burning his very muscles. His mouth clenched fiercely around his wand, refusing to open, refusing to let out his pain in a blood-curdling scream, his wand the only meagre sense of support in this sea of anguish his body had been thrown into.

Then, just as suddenly as it had begun, it was over. As his senses started to work again, he recognized the harsh, panting sounds as his own breath, and slowly became aware of a hard cold surface below his cheek. Forcing his eyes open, he was not very surprised to find himself lying on the floor. Although he had no recollection of having fallen down, he had been in this situation enough times to expect it by now.

Sitting up, he attempted to take deep breaths to slow down his racing heart. Realizing that he was still clenching his wand tightly in his mouth, he spat it out, sparing it only a brief glance, wondering vaguely if he should replace if with something else before it broke in two. It was already showing signs of wear and tear, covered in bite marks showing how often he had used it to stifle his cries. It was not only that he did not want anyone to be alerted by noises inside the room, no, that would have been easy solved by a Muffliato charm. It was not the people outside he was worried about, it was the person standing in this room, the one who had cast the spell that concerned him. His pride would not let him reveal his pain in front of one of his students, especially if that student happened to be Harry James Potter.

Said Harry James Potter was now moving towards Snape, his face a mixture of concern and disgust. He offered a hand to Snape to help him up- more out of habit than anything else- because as always Snape simply batted it away with a scowl, opting rather to stand on his own, slowly, painfully, each time weaker than the time before, but eventually making it to the armchair behind his desk, where he sank down gratefully.

Gesturing to Harry to sit down in the chair opposite, Snape permitted himself to rest for a while, head leaning back against the soft back of the chair, eyes closed, his thoughts drifting back to his first lesson with Potter. The boy had improved greatly since then. The first few days had proven to be complete disasters, he remembered. Snape had expected that the 'Golden Boy' would be unable to find the anger and hatred within himself needed to cast an Unforgivable, and so after a few ineffectual spells which confirmed this, Snape had moved to take matters into his own hands.

He cast a silent Legilimency spell and harshly tore through the various images that came rushing up, not having to look long before finding the one of Sirius's death. He held on to that image, playing it over and over again willing Potter to remember that day, how angry he had been at Snape, blaming him for Sirius's death, how much he wanted to have his revenge. He tore through Potter's other memories, finding previous happy moments with Sirius, projecting them to the front, forcing him to remember all that he had lost, the bitterness and grief he faced supposedly because of Snape.

That did provoke a reaction, but the spell Potter cast was brief and short-lived, barely causing Snape to twitch.

Again and again Snape repeated his method, prying through his mind, looking at memories that he knew Harry would want to keep private, and would get angry if anyone else saw them. He lingered over embarrassing moments, memories of a young Harry crying because of some injustice of the Dursleys, of the kiss shared with Cho Chang under the mistletoe, daring Harry, challenging him to fight back and stop him if he could by using the spell. He drew out every snippet he could find about his parents and Sirius, tearing up wounds that had long been hidden and buried and rubbing salt in them again. He could feel Harry trying to shove him out of his minds, but he had after all never managed occulemency, so Snape just ignored his weak efforts and continued his mental assault. And when all his mind-racking still only produced the most minimal of curses, he left his mind and taunted him, sneered about his worthless parents, how the world was better off without them, how he wished he could have killed them himself. Harry would get mad with rage, screaming and yelling, trying to take out his anger by throwing lesser curses at Snape, Stinging hexes and other jinxes, all of which Snape blocked easily, forcing Harry to use only one path to lash back at him.

And he had done it. It had taken almost a week with practices every night, but finally Harry had been pushed to the furthest limit, and had lashed back with an immensely powerful Cruciatus curse, which would have even put some of the lower-ranking death eaters to shame. Since then it had taken another week of nightly practices, before Harry was able to cast the spell without provocation and with enough power to make Snape writhe in agony. There was no doubting that Harry did have the potential to be a great wizard, Snape could sense the immense well of natural power in him, which once it had been accessed, helped Harry to cast more and more powerful curses.

Even while Snape's mind was pleased with this progress, his body screamed in protest at the daily dose of torture he subjected himself to. Every night for a week the same scene had been replayed; the same horrible curse, the same terrible pain. His muscles ached throughout the day from the aftermath of the curses, bruises were starting to from on his chest where the spell hit him directly, a natural effect of prolonged use of the curse, his knees hurt from crashing against the stone floor every time he fell down in his agony. Even his teeth felt stiff after clenching his wand so tightly.

But his body's concerns were irrelevant in light of the importance of what needed to be done, so once again he pushed down its complaints and focused his attention back on the present.

Gazing appraisingly at Harry, he said, "That was good, Potter. More powerful and longer than the last time. Many grown wizards would not have the power to cast that."

Harry looked surprised. It was probably the first time he had received such an outright compliment from Snape, without any back-handed insult in it. 'It's ironic, isn't it?' he thought. 'The first time he praises me, and then for something I would never wished to be praised for.'

Aloud he asked, "So, is it over now, am I prepared enough? Can we stop doing this?"

Snape smirked at him. "Why, didn't you enjoy my company? Are you so anxious to leave? Strange, I was under the impression that you were having the time of your life, getting the chance for the revenge you have always wanted."

Harry said nothing, too drained to even feel anger at Snape anymore. The Cruciatus curse left him exhausted as no spells previously did. The moment the spell ended, his body would feel worn out and shattered, a feeling that stayed with him throughout the day.

Snape must have noticed this, for he asked in a slightly softer tone, "What's the matter, Potter? No insults, no witty comebacks? Silence from you, while really pleasant I must admit, is highly unusual."

Harry hesitated a bit before answering. He could tell that despite the taunts, Snape was genuinely concerned. His exhaustion must have been really obvious then. Deciding to finally unburden himself, he confessed, "I feel…exhausted, Professor. It's as if the spell takes with it all my energy, everything I have inside. No other spell has done that before, made me feel just so horrible."

"The Unforgivables are not like any other spell, Potter," Snape said. "They require a tremendous amount of magical power, and it is natural to feel tired at first, when you are not so used to casting them. But more then just the power they require, it is the nature of the spell itself that makes you feel as you are feeling now. Have you thought about why they are termed Unforgivables, Potter? It is because these three spells go against the very basis of human nature itself, they are so contrary to human nature that using them against another human being is like committing a sin against humanity. And that is why casting them feels so terrible, feel so wrong because it is wrong, it is the most wrong you can ever do. Killing is never easy, it is not meant to be. You feel almost as if you are loosing a part of your soul. It is the same philosophy as that of the horcruxes, Potter, doing something so evil that it splits your very soul."

Harry looked up in shock at this revelation. He had never really connected the two together like that, but what Snape was describing was exactly what he was feeling. Looking down at his hands, Harry said in barely a whisper, "It feels so bad knowing that I can cast such a spell. I would never have believed that I could hold such evil inside me." Harry laughed, the sound hollow and mirthless. "I guess this makes me the same as him doesn't it?

It was something Harry had been thinking of for some time now, ever since he had first cast the curse, and what Snape explained today only made it worse. What right had he to call Voldemort evil when he was just as capable of doing the same evil as him? As he improved in casting the curse he became more and more horrified as what he was doing. To so casually, without provocation use that kind of evil daily against someone who had not really even done anything to him…how did it make him any better than Voldemort?

"Well, Potter," Snape replied, "If you would only think a little deeper I am sure that you would see the stupidity of that question. I could recite for you a million ways in which you are different from the Dark Lord, that the Dark Lord has used the curses infinitely more times than you ever will, that he has used it on the innocent where you will use it on the guilty, that he has destroyed the world with it and you will be helping to save it, all of the many things that anyone will be able to tell you, truthfully, that make you different from him."

"But," Snape continued, "You have stumbled on a very important realization, the fact that you _can_ be the same as the Dark Lord. Let me ask you something. Do you remember the feeling you get when you actually cast the curse? I don't mean the drained out feeling after it is over, but during the actual casting of it?"

Harry shifted guiltily in his seat and averted his eyes. He had spent the past week trying to convince himself that he had felt nothing, because the implications of what he had felt were something he did not want to consider.

Snape must have noticed his movements, for he continued without waiting for an answer, his tone now mysterious and strangely warm. "I see you know what I am talking about. It is nothing to be ashamed of, it is not unique to you, it is just an emotion that accompanies the curse. It is the feeling of immense power running through your body, the joy of mighty supremacy, the ecstasy of raw strength, the satisfaction of crushing your enemy beneath your heels. You can feel it rising inside of you, a dark, ancient, elemental force, and at that moment you know without doubt that you hold the reins of the world in your hand and you_ love it_. And all you can think of is what you would give to be able to cast this again and again. It is an addiction, the world's most tantalizing drug. It is the seduction of the dark arts, stronger than any love potion; the alluring temptation that draws you in willingly even eagerly and then entraps you in its charms. Even when you see the effect of all you have done, when you know how wrong it is, you cannot stop hearing its call, longing, ever-longing to feel that raw power, that immense joy."

Snape's voice faded into the silence of the room. He was no longer looking at Harry, not even seeming to realize he was there, his eyes holding a far-away quality as if he was lost in memories only he knew. Harry waited awkwardly for Snape to continue, wanting something to break the surreal silence that stretched between them, but somehow not daring to do it himself. Snape's words had left him uncomfortable. He could not deny that that was exactly what he was feeling, but hearing Snape talk of how he felt with an almost loving caress in his voice was…disturbing to say the least.

Luckily, Harry did not have to wait long. Snape suddenly snapped out of his reverie, seeming slightly shocked to see Harry there, as if he had completely forgotten he existed. Gathering his thoughts, he once more focused his attention on Harry, his voice back to his business-like tone.

"If you understand this, Potter, you will understand how easy it is to become like the dark lord, how easily you could truly become the same as him. You will begin to see, I hope, the truly seducing power of the dark arts. It is the trap all dark wizards have fallen into. The start is usually innocent, a quest for knowledge, a desire for power. But one taste of that power, and the desire becomes a hunger, an obsession that overrides everything else. The overpowering appeal of the dark arts is what makes them so dangerous because anyone can fall prey to it, no matter how good and upright he used to be. It is imperative that you understand this, Potter, I cannot stress this enough. It is the most important thing that separates you from the Dark Lord. He has given in to this temptation, you must not. The moment you start craving that feeling, wanting to perform the curses again just to get that ecstasy of power, enjoying what you are doing instead of seeing it as a necessity, that is the day you will become the same as him."

Snape fell silent, his eyes still fixed on Harry, watching him as he tried to process everything he had just been told. It would take him some time to come to grasps with it, but it was very necessary that he understood that he had to resist the seductive power that had pulled so many others to their own destructions. It was a great burden for one so young to bear. He knew, oh yes Snape knew how hard resisting that power could be. After all, he was not much older when…

No, he would not think of that now. Those memories would come back to haunt him in the silent dark of the night, he knew, but not now.

Forcefully pushing his thoughts away from that direction, Snape glanced at the clock. It was still early, but Snape had a feeling that further practice that night would not prove very effective. And they could both use a break right now.

"Let's call it a night, Potter." Snape said, drawing Harry's attention back to himself. "We'll start again tomorrow, at 8 sharp."

Harry looked up at him, a pleading look on his face. They had come back to the beginning, to his very first question. How much longer, Harry wondered, how much longer would this go on. How much longer could they both take it? "Please, Professor." He said. "Can't we stop doing this now? I don't want to do this any longer. Isn't it enough?"

Snape's body screamed at him to say yes, every fiber of his being wanting him to take this escape presented to him. But he knew that however powerful Harry's curse currently was he would still need a lot more practice to be sure that he could cast the Avada Kedavra when it was time. So he just kept his face impassive and shook his head, watching as Harry's face fell in disappointment.

"How much longer? When can we stop?" Harry asked quietly.

Snape contemplated the question for a moment. There was no way of fixing a specific date or time period because he did not know how fast they would progress. And how would they be able to judge when he was prepared enough? Thinking through it, Snape reached a decision and replied, "When you make me scream."

Harry accepted this without question, and nodding slightly moved towards the door. Pausing with his hand on the doorknob, he turned around and said softly, "Thank you, sir.", before leaving the room and shutting the door gently behind him.

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A/N: Well, there it is! I really hope you liked it. Review, please!  
And if anyone was wondering, this is set at the beginning of the sixth year, so Harry shouldn't by right know about the horcruxes yet. But, well, this is kind of AU, so I'm just pretending that Harry already knows… 


	4. Burden of Sin

Disclaimer: See first chapter.

A/N: Well, here's the last chapter, after a very long wait. Sorry about that, but many things got in the way. Thanks to everyone who reviewed the last chapter! Your kind words mean a lot to me. I will reply to everyone who logged in, hopefully today or tomorrow.  
This chapter is dedicated to a certain friend of mine…you know who you are…I hope you enjoy!

Warning: There is a mild bit of swearing in this chapter. It's really very little (just one word in fact), but if that sort of thing offends you, please read with caution.

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Chapter 4 – Burden of Sin

Nights had fallen on the grounds around Hogwarts. The swift bustle of the day had given in to the unbroken peace of the night. The castle stood dark and silent, its occupants long since having surrendered to sleep and dreams. Well…most of them anyway.

The fire crackled softly in the hearth in a small room next to the dungeons, the only source of light in the room. The leaping flames faintly outlined the figure of a man, sitting in a deep armchair near the fireplace. He had been sitting there for quite some time now, unmoving, dark onyx eyes staring deep into the flames as if trying to unearth some mystery hidden within. In his hand he clutched a half-full glass of wine, his occasional sips the only other sound to disturb the silence that lay heavy in the air.

Despite the lateness of the night, Severus Snape had yet no desire to seek out his bed. His calm and relaxed posture belied the chaotic tumult of thoughts going on inside his head that would not allow him any rest.

Shifting slightly in his seat, Severus winced as the small movement renewed the ache in his body. Sighing, he once again settled back into the cushions. "More wine" he thought to himself, and as if to prove his point he took another deep sip from the glass in his hand, which magically refilled itself again. He was not a frequent drinker, but on some nights like this when everything became too much, he craved the numbness of alcohol, to just be able to not feel. Judging by the still-present pains of his body he still had some way to go. The after-effects of the Cruciatus curse lingered for quite some time after the spell had actually been cast and to have suffered them so repeatedly as he had only made it worse.

And of course, there was still a long time to go. His thoughts drifted back to the earlier events of the evening, his mind replaying the scene for the millionth time. "When you make me scream" he heard himself saying over and over.

No matter how powerful the curse now was, Severus knew that it would still be some time before it would actually force a scream from him. No, he did not delude himself by thinking that he would never break - every man had a breaking point, he knew this better than anyone – but he also knew his own endurance. This coupled with his stubborn refusal to disgrace himself before anyone especially Potter meant that he would have to suffer through many more nights of torment before his will finally broke and he could be rid of this hell. For once in his life he actually cursed his strength for not letting him simply take the easy way out and get out of this sooner.

But it was not only the pain that bothered him tonight. Oh no, he was well enough used to pain by now.  
Severus's thoughts swirled further into the past, to the early days of his childhood and even there he found only a well of despair. Images of his life came rushing at him fast and furious; the angry, red face of his father, the whistling crack of his belt, while his mother sobbed in the corner melded into the sneering, taunting face of Potter and Black as they tormented him in front of the whole school and that image gave way to a man with a flat, snake-like face with slitted holes for nose and cold red eyes holding up his wand and the sound of the cruel laughter that surrounded him as he writhed on the floor. The memories spun around him, the laughter, the faces, the pain, and it seemed that most of his life, indeed, had just been a constant string of agony and torment. Always, always more pain, more torment.

So the physical pain of his body was not the main concern on his mind. It never had been. What he hated the most was the humiliation and helplessness of his situation.

Every day it was harder to stand up in front of Potter, defenseless, to put himself at his- at anyone's- mercy knowing that he could do nothing to stop them from doing as they willed. He hated the sense of vulnerability and it infuriated him to have to hand over power and authority over himself to someone else. After all, throughout his youth he had always seen, experienced first-hand what a bad idea it was to have anyone more powerful than you around you, what they could do to you, with great pleasure no less. The very first lesson he had learned about life was that anyone who was stronger than you would take advantage of you, so you must not remain defenseless against them. He had spent years trying to erase that sense of defenselessness, developing his magical skills, putting his faith in knowledge learning all he could to make sure no one would ever hold power over him again. And he had succeeded hadn't he? At his schooling days in Hogwarts he had been doing spells, inventing spells that many adult wizards could not manage.. But it had made no difference. Even his belief in intellectual strength and knowledge had proven hollow. It was one of the great ironies the pervaded his life.

Now that he had the skill and the power to revenge himself on his tormentors, he no longer had the opppurtunity to do so. Even to this day he had to crawl to the Dark Lord, fawn at his feet, kiss his robes like some pathetic half-wit when his hands were itching to fight against him. He had to surrender himself to the whims and fancies of the Dark Lord, practically invite him to torture him, and force himself to stand defenseless and helpless in front of him - in short immerse himself in the very situation and emotions he had vowed to himself he would never again be in. It was like leading himself to the guillotine. And now this thing with Potter only added to his misery. Sure, he was a powerful wizard, he might even be one of the best duelists in the world as Dumbledore claimed, but he was still here getting tortured by a sixteen year old. Snape gave a bitter, self-mocking laugh. All those years trying to best Potter and his friends, constantly protecting himself from their pranks and spells and now he was standing in front of Potter's own son and asking him, no, forcing him to torture him. Life was a bastard wasn't it?

Definitely more wine needed.

And there was the other reason he hated this whole business, hated himself for doing it. If what he had said to Harry was true -and it was- if the Unforgivables were the greatest evil one could do, what did that say about him, to be knowingly leading another down that path of wickedness?

Teaching an innocent to kill. Teaching an innocent to cause pain. Another sin he could add to his head.

Thirteen years it had been since he had renounced that path himself, sworn that he would never again commit the deeds that were till now the greatest shame of his life. He had hoped at some level to redeem himself by returning to the 'good' side. But he had succeeded only in further blackening his own soul. Should it really matter by now? What was another dark mark on his by-now completely blackened soul?

The memories came back to him, and in this darkness of the night he had no shield against them. This was ever the time when they would attack him. They were too powerful, emotions that he had long hidden inside him overwhelming him with their intensity.

He saw once again in his mind's eye the images that he visited too frequently in his nightmares. He remembered the petulant face of the child with the sunken, dark-rimmed eyes, mop of greasy hair, pale complexion and the scowl that others would later say he had almost patented. A bitter and angry child, alone, frightened, hated by and hating everyone else in the world. His one desperate comfort was books, in his desolate solitude he had often sought the comfort of intellect and wisdom. Books were his friends, who would not desert him, knowledge his strength that would not fail him, his key to acceptance. Everyone would have to pay attention to him if he was smart and skillful. The young boy had absorbed all kinds of spells like a sponge, hungrily, often surpassing his peers in his work. His attention was ever drawn to the dark arts, the infinite well of spells constantly feeding his fire of learning. He was always looking for and devouring harder and harder spells. It was not much of a surprise that he had eventually stumbled across the Unforgivables, - and he was never the same since.

Snape could remember the first time he had cast an Unforgivable. It was everything he had described to Harry and more. It had seduced him on his first attempt, and ever since then he was drawn deeper and deeper into it, seeking and loving the ecstasy of raw strength. It had given the young, hurting boy everything he desired. It was his chance to repay all those who had wronged him, to show the world he was not a weakling to be made fun of and ridiculed, to for once be the one who was stronger.

The memories of his misguided teenage years crashed down upon him. Supporters of Voldemort were ever increasing in number, and it was by far the most popular career choice among the Slytherins. For the young Severus Snape, it had been the most exciting prospect he could have imagined. To serve under the most feared lord of the century, to gain the power and control that had so long being denied to him, to be given the chance to be the one holding the reins…it was a dream come true.

The older Severus Snape, let out a bitter snort of laughter at this recollection. A dream? More like a nightmare.

His first few months were indeed enjoyable. For the first time, he felt like he was wanted, that his skills were appreciated and his great talents put to use. He had risen through the ranks rapidly despite being so young, garnering praise even from the dark lord himself. It was most probably the best few months in his life.

"But I was blind then, blind to everything but the power" Snape thought to himself darkly.

He tried to recollect the exact moment when his eyes had opened, when he had seen the true nature of what he was doing, but could not. Perhaps it was the razing of the muggle village he used to live in as a child, perhaps the torture of that young girl with the bright blue eyes that had stared at him so pleadingly, or perhaps, perhaps it was the knowledge that _she_ was to be the dark lord's next victim. To know that the bright spark of life in those startlingly green eyes was to be lost forever. Yes, that was probably what pulled him back. In a matter of days, his time of greatest pride was turned into one of greatest shame.

If Snape was thankful for one thing in his life, it was that he still had enough sense left inside him by then to recognize what he had done and turn away from the path when given the chance. He had found some speck of humanity that had not yet been destroyed by his black sins. He had gone then to Dumbledore to atone for his sins, and to this day was serving what he considered to be punishment for his wrongs.

But no matter what he did he could not consider his debts even the slightest bit fulfilled. He didn't think he could ever do enough to make up for his past actions. The faces, the eyes still haunted him. No amount of wine could drown them out. If they could he would have drunk himself senseless long ago. Even if he lived for all eternity, he would never be able to forget the screams of the innocent, the blood splattering his robes, the look in the eyes as life finally left them, the soft, warm body falling still and lifeless against his, the stench of death. Never, never for one moment had he forgiven himself for what he had done. Never had the screams let him forget.

But what shocked Severus even more was how hard pulling away was. His entire mind, body and soul were repulsed at the thought of ever doing those things anymore, but somewhere inside him some part of him still craved the feeling of the Unforgivables. It shamed him to admit it, but despite all that had happened he could not get rid of their addiction. He had managed it somehow but it was not easy. The trap they laid for you ensnared you for life. Even now whenever he recalled that moment of pure, simple, divine joy, his heart would quiver with desire, his hand itch towards his wand. He had not exaggerated their power to Harry.

Harry. That was where it all came back too. Despite all his qualms for these lessons, they were unavoidable. This was war after all, and as much as Snape might hate to be put in such a position, it was not meant to be clean or fair or nice. Harry had to learn to kill and that was all there was to it. And he had learned quite fast, Snape had to admit.

But the curse in itself was not the most important lesson. Anyone could learn it, given time. The most important lesson – and the hardest, he knew- was what they had discussed today. Not crossing that thin but vitally important line between good and evil. Once you had, it was a one-way road to destruction, there was no redemption, he knew that now, he was the living example of it now.

If only someone had told him all this when he was young. If only someone had cared enough to notice the way his disastrous steps were taking him, to stop him before he got too far, one less soul would have been lost. But he would not now rail at the world and at his fortunes. He had made his choices, however misguided, and he took the blame for them. He could not now change them, but he could make sure that another child was not lost to the darkness.

What mattered most to Severus was making sure that Harry did not go down the same way he did. He would be truly beyond redemption if he led another to the horrors of the path he had gone through. He had to teach Harry to kill but he would not teach him to be a murderer, he would teach Harry to defeat the Dark Lord, not become another in his place.

Perhaps than the burden of his sin could be lightened. Perhaps.

* * *

A/N: Well, that's it! It's the end. I know some of you were probably expecting a longer story with an actual plot, but I had always planned this as just a short one-off thing. I hope you enjoyed it in any case.

I'd love to hear what you thought about this chapter, because I had a hard time writing it. Thanks for reading!

Until next time,  
fire-forged


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